The invention relates generally to semiconductor-on-insulator hetero-structures. More particularly, the invention relates to reduced defect semiconductor layers within the context of semiconductor-on-insulator hetero-structures.
Semiconductor structures typically comprise semiconductor substrates within and upon which are formed semiconductor devices, such as but not limited to resistors, transistors, capacitors and diodes. The semiconductor devices are connected and interconnected using patterned conductor layers that are separated by dielectric layers.
As semiconductor technology has advanced, semiconductor substrate materials have also evolved from generally conventional predominantly silicon containing semiconductor materials (i.e., greater than 50 atomic percent silicon) to include alternative semiconductor materials, such as predominantly germanium containing semiconductor materials (i.e., greater than 50 atomic percent germanium), as well as compound semiconductor materials. For example, predominantly germanium containing semiconductor materials and compound semiconductor materials are desirable insofar as predominantly germanium containing semiconductor materials and compound semiconductor materials often provide a higher carrier mobility in comparison with predominantly silicon containing semiconductor materials.
As an adjunct to the evolution of predominantly germanium containing semiconductor materials and compound semiconductor materials within semiconductor fabrication, there has also evolved semiconductor-on-insulator substrates in comparison with bulk semiconductor substrates. Semiconductor-on-insulator substrates are desirable within the semiconductor fabrication art in comparison with bulk semiconductor substrates insofar as semiconductor-on-insulator substrates provide superior semiconductor device isolation. In conjunction with different semiconductor materials for a base semiconductor substrate and a surface semiconductor layer within a semiconductor-on-insulator substrate a further evolution within semiconductor fabrication involves the fabrication of semiconductor-on-insulator hetero-structures.
Although predominantly germanium containing semiconductor materials and compound semiconductor materials are thus desirable within the context of semiconductor-on-insulator hetero-structures within the semiconductor fabrication art, predominantly germanium containing semiconductor materials and compound semiconductor materials within the context of semiconductor-on-insulator hetero-structures are nonetheless not entirely without problems. In that regard, predominantly germanium containing semiconductor materials and compound semiconductor materials within the context of semiconductor-on-insulator hetero-structures are often difficult to fabricate absent crystalline defects, such as but not limited to stacking (i.e., misfit) dislocation defects and threading dislocation defects.
Thus, desirable within semiconductor fabrication are methods and materials that provide for reduced defect (i.e., less than 10e6 defects per square centimeter and more preferably less than 10e5 defects per square centimeter, and still more preferably less than less than 10e4 defects per square centimeter) predominantly germanium containing layers and compound semiconductor layers within semiconductor-on-insulator hetero-structures.